Article ID: 322156 - View products that this article applies to.
This article was previously published under Q322156
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When you try to install Microsoft Message Queuing (also known as MSMQ) 2.0 Client or Server, the installation may fail, and you may receive the following error message:
Error: Unable to Load MQQM.dll
Error Code: 0x7F
This problem occurs if you uninstalled Message Queuing after you installed a Message Queuing hotfix or security update and are now reinstalling Message Queuing. This problem occurs because of mismatched service DLLs.
Before Message Queuing is installed, several of the DLLs are maintained on the system that has the default OS installation. When Message Queuing is installed, additional files are installed to complete the service. If a hotfix or an update has been applied, and Message Queuing is then uninstalled, the files that are installed when the component is added are removed. However, the newer updated files that are installed during OS installation remain resident but are updated.
When Message Queuing is reinstalled, the newer files are left installed. However, the most recent service pack DLLs are installed to complete the Message Queuing installation. This causes a version conflict that results in the error message that is mentioned in the "Symptoms" section.
To resolve this issue, check the version of MQQM.dll in the System32 folder. If the version is 22.214.171.1248, follow these steps: